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Personality: Ahead of his times
G regor J. Mendel (1822-1884) was a great scientist and the founder of genetics. Also called Mendelian Genetics or Classical Genetics, the discipline deals with inheritance. Like any other branch of science, genetics has developed quite rapidly. From the chromosomal level it has developed to the molecular or biochemical level.
Gregor Mendel, seen as a failure by his contemporaries, had to wait for decades before his discoveries in genetics received their due share of laurels
In addition to the advancement of theoretical knowledge, its practical application is sought through the fast growing field of genetic engineering. This important branch is presently used for developing genetically modified food with high yields and resistant varieties of crops. As long as genetics exists, Mendel cannot be forgotten.
Mendel was an Austrian scientist. In 1850 he applied for a position at the high school in Altbrunn, but failed examinations in natural sciences. The examiners wrote that the candidate had not mastered the subject sufficiently to qualify for lectureship at the school.
Disappointed, Mendel returned and several months later appeared for a second examination, which he failed. The examiners remarked: “This second examination paper would hardly allow us to regard the candidate as competent to become an instructor even in the lower school.”
Such was the verdict of the contemporary experts on the scientific ability of one of history’s outstanding scientists. Mendel’s failure in examinations was due to his originality.
His writings were way too complex for examiners to understand. According to his examiners, Mendel paid no attention to technical terminology, and used his own words and discussed his own ideas instead of depending on traditional knowledge.
It was in Mendel’s blood to select a course of action or to develop a train of thought and to pursue it to the end, despite all opposition. His love for nature, like his tenacity of purpose, was the result of his lineage as he descended from a line of peasants and gardeners. His father was a peasant by profession and Mendel was brought up with a passion for growing plants. He spent many hours in his childhood tending plants in his father’s garden. By observing and tending the plants he developed an early love for different trees, fruits and flowers. He was always curious to know as to what it was that gave colours to flowers and different shapes to fruits and trees.
Mendel’s parents were very poor and could not support his education. Coupled with ill health, his studies were almost at the brink of disaster when he received financial help from his married elder sister, Veranika. Encouraged, Mendel took up the study of philosophy at the Olmutz Institute and after four years of hard work, occasional illness and perpetual hunger he was finally at the threshold of his career.
The question Mendel now faced was, what should his career be? He consulted one of his teachers, Prof Michael Franz, who recommended a monastic life which he felt was best suited to meet Mendel’s requirements. Thus, in October of 1843 Mendel entered the Augustinian monastery at Altbrunn.
Shortly before his arrival at Altbrunn, a botanical garden had been planted under the supervision of one of the monks, Father Aurelius Thaler, a botanist noted for his interest and competence. When Mendel came to the monastery, Thaler had died but had left behind a well-stocked and scientifically tended garden.
This garden for Mendel was a gift from God. He spent all his spare moments there and found himself in a congenial group — both temperamentally and intellectually. In the evening, the group discussed theology, literature, philosophy, science and occasionally politics.
The 1840s were a revolutionary era, and men were opening their minds to new thoughts and vision. Even though some of the Mendel’s associates left the monastery, Mendel preferred to remain there. He was interested in teaching as well as studying, so he applied to the local high school and got a job.
He continued to live at the cloister and to cultivate plants in its garden. Mendel was interested in cross-fertilization of the common pea. He hoped, through his study of heredity of plants, to learn something about the secret of the heredity of man.
How can we explain the many shapes of living things? In order to find a possible answer to the question, he asked for a small plot of land on the monastery premises and proceeded to transform it into a living book. He selected 22 varieties of sweet peas in different shapes, sizes and colours.
He mated, remated and transmated them for seven years and carefully noted the different characters of successive generations. The summary of characteristics he discovered in the successive generations of the offspring is given briefly in the following.
— When two different types of plants (or of animals) are mated, all the offspring of the next generation will be alike. This is called “the Law of Uniformity.” For example when you cross a red flower with a white flower, all the offspring will be pink.
— When the uniform offspring of the different plants are mated, the resulting offspring will not be uniform, but will segregate themselves into different forms according to a definite numerical ratio. This is called “the Law of Segregation.” For example, if you cross the pink flowers that have sprung from the cross between red flowers and the white flowers, out of every eight offspring two will be red, two will be white, and four will be pink.
— The crossing of red flowers of this generation will always produce red flowers. The crossing of white flowers will always produce white flowers. The crossing of pink flowers of this generation, like the crossing of the previous generation of pink flowers will produce out of eight offspring two red flowers, two white flowers and four pink flowers. This “Law of Proportional segregation” will hold true of every successive generation of hybridisation of plants or animals.
Such was the mathematical design that Mendel discovered in the law of physical inheritance of living and growing things. It took him seven years to make this discovery and the world thirty years to realize its importance. When Mendel first read his paper on plant hybridization before the Altbrunn Society for the Study of Natural Sciences, his audience listened politely, applauded faintly and promptly forgot the whole thing. Despite that he published the paper, which unfortunately lay neglected on the dusty shelves of a few libraries.
The writer is a former senior scientific officer of PCSIR
The he and she of itW hen Gregor Mendel proposed that in any living thing, each trait is determined by a pair of genes, it presented a potential problem. If parents pass on both copies of a gene pair, then offspring would end up with four genes for each trait. Mendel deduced that sex cells — sperm and eggs — contain only one parental gene of each pair. The half-sets of genes contributed by sperm and egg restore a whole set of genes in the offspring.
Mendel also found that different gene combination from the parents resulted in specific ratios of dominant-to-recessive traits. The result of a cross between two hybrid parents — each carrying one dominant and one recessive gene - were key to his synthesis. For example, a cross between two yellow-seed hybrids produced three times as many yellow seeds as green seeds. This is Mendel’s famous 3 to 1 ratio.
Mendel published his research, Experiments in Plant Hybridization, in 1865 and sent reprints to prominent scientists in several countries. However, his abstract notion of genes was not appreciated by the naturalist of his time - who had been trained primarily to observe and categorize living things. Mendel’s work lay fallow until 1900, when three European scientists independently confirmed his results. Although Mendel’s law was first tested in pea plants and fruit flies, evidence quickly mounted that they applied to all living things. Pedigrees of families affected by diseases provided many of the first examples of Mendelian inheritance in humans.
There was obvious interest to applying Mendel’s laws to agriculture. The ideas were also embraced by the eugenics movement, the goal of which was to improve the human species by better breeding. Eugenicists encouraged marriage between peole of ‘good genetic stock’ and discouraged reproduction of genetically unfit.
Eugenicists wrongly used simple dominant/recessive schemes to explain complex behaviours and mental illnesses — which we know now involve many genes. They also failed to account for environmental effects on human development.
The eugenic description of human life was finally discredited by horrible consequences of the Nazi quest for racial purity. — http://www.dnaftb.org
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